276 algebra De mystif ieD
The equation to solve is^1
3
11
2
+ =
t
. The LCD is 6t.
1
3
11
2
6 1
3
1 6 1
2
6 1
3
6 1
+=
+
=
+
t
t
t
t
tt
t
=
+=
−−
=
3
263
22
6
t
tt
tt
t
Brandon can split the wood-pile by himself in 6 hours.
- Worker Quantity Rate Time
Boy 1 1/90 90
Girl 1 1/60 60
Together 1 1/t t
The equation to solve is^1
90
1
60
+ ^1 =
t
. The LCD is 180t.
1
90
1
60
1
180 1
90
1
60
180 1
180 1
90
+=
+
=
t
tt
t
t
+
=
+=
=
=
180 1
60
180
23180
5 180
180
5
t
tt
t
t
t== 36
Working together, the boy and girl need 36 minutes to weed the garden.
- Worker Quantity Rate Time
Robert 1 1/40 40
Paul 1 1/20 20
Together 1 1/t t